Re: [PATCH] selftests/landlock: fix broken include of linux/landlock.h

[Mickaël Salaün]

On 04/08/2022 21:38, Guillaume Tucker wrote:
> On 04/08/2022 12:36, Mickaël Salaün wrote:
> > On 03/08/2022 22:13, Guillaume Tucker wrote:
> > > Revert part of the earlier changes to fix the kselftest build when
> > > using a sub-directory from the top of the tree as this broke the
> > > landlock test build as a side-effect when building with "make -C
> > > tools/testing/selftests/landlock".
> > >
> > > Reported-by: Mickaël Salaün <mic@xxxxxxxxxxx>
> > > Fixes: a917dd94b832 ("selftests/landlock: drop deprecated headers dependency")
> > > Fixes: f2745dc0ba3d ("selftests: stop using KSFT_KHDR_INSTALL")
> > > Signed-off-by: Guillaume Tucker <guillaume.tucker@xxxxxxxxxxxxx>
> > > ---
> > >    tools/testing/selftests/landlock/Makefile | 7 +++++--
> > >    1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile
> > > index a6959df28eb0..02868ac3bc71 100644
> > > --- a/tools/testing/selftests/landlock/Makefile
> > > +++ b/tools/testing/selftests/landlock/Makefile
> > > @@ -9,10 +9,13 @@ TEST_GEN_PROGS := $(src_test:.c=)
> > >    TEST_GEN_PROGS_EXTENDED := true
> > >      OVERRIDE_TARGETS := 1
> > > +top_srcdir := ../../../..
> >
> > Not sure it changes much, but most other selftests Makefiles use "top_srcdir = ../../../.." (without ":="). Why this change?
>
> I didn't simply apply your diff but edited the file by hand to
> test various combinations and see what side effects it might
> have.  So when I added top_srcdir I typed it by hand and used :=
> as a reflex since it's the standard way of assigning variables.
> Using = instead only makes a difference when the r-value has
> something dynamic as it will be re-evaluated every time it's
> used.  So for constant values, I guess it's more of a question of
> coding style and conventions.  Maybe all the top_srcdir variables
> should be changed to := but that's unnecessary churn...  Either
> way, it's benign.
>
> Shuah, feel free to change this back to = in this particular case
> if it's more consistent with other Makefiles.  Consistency is
> often better than arbitrary rules.  Or conversely, change to :=
> for the khdr_dir definition...  Entirely up to you I think.

Looks good to me, thanks! Shuah, feel free to add
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>

> Thanks,
> Guillaume
>
> > >    include ../lib.mk
> > >    +khdr_dir = $(top_srcdir)/usr/include
> > > +
> > >    $(OUTPUT)/true: true.c
> > >        $(LINK.c) $< $(LDLIBS) -o $@ -static
> > >    -$(OUTPUT)/%_test: %_test.c ../kselftest_harness.h common.h
> > > -    $(LINK.c) $< $(LDLIBS) -o $@ -lcap
> > > +$(OUTPUT)/%_test: %_test.c $(khdr_dir)/linux/landlock.h ../kselftest_harness.h common.h
> > > +    $(LINK.c) $< $(LDLIBS) -o $@ -lcap -I$(khdr_dir)